Burgess made the switch to union after winning the NRL title with South Sydney Rabbitohs last year, but has come in for considerable criticism for his performances at the Rugby World Cup.
Indeed, some have cited his selection by Stuart Lancaster as a reason for England's failure to make it out of their pool.
As a consequence, speculation has mounted that Burgess could make a swift return to league after less than a season with Premiership outfit Bath.
"At some point I am sure he will come back - whether that is six months, 12 months, three years, five years, who knows," McNamara told the BBC.
"It is the game he was brought up with."
McNamara is currently preparing his England side, which includes Burgess' brother Tom, for a three-Test series against New Zealand.
"People always want to point the finger at someone else.
"I couldn't be more proud of Sam. He deserves huge credit for being one of the world's best at rugby league, then to give it away to challenge himself in a really uncomfortable environment and be an international in the space of 12 months."